Range heat indicator



2,823,638 Patented Feb. 18, .1958

RANGE HEAT INDICATOR Elmo E. Aylor, Galesburg, and Don C. Sevey,Abingdon, Ill., assignors to Midwest Manufacturing Corporation,Galesburg, 111., a corporation of Illinois Application June 13, 1956,Serial No. 591,208

7 Claims. (Cl. 116-124) This invention relates generally to anarrangement for giving a visual indication of the heat setting of aheating unit, and is particularly directed to such an indicator forelectrical cooking apparatus, such as an electric range.

Commonly in electrical cooking equipment, such as ranges, fry pans andthe like, the heat setting of the cooking element is under the controlof a thermostat, which in turn is under the control of a manuallyoperated device, such as a rotatable control knob. While the controlknob setting in such equipment usually tells the temperature for whichthe heating element is set, it is advantageous to provide an auxiliaryvisual indicator which will more strikingly call to the operatorsattention the heat setting of the equipment. The present invention isdirected to such a visual indicator.

It is an object of the present invention to provide on a heatingapparatus a novel arrangement for visually indicating its heat setting.

It is also an object of this invention to provide on electrical cookingapparatus a novel visual indicator arranged to effectively call to theusers notice the heat setting of the apparatus.

Another object of this invention is to provide a novel visualheat-setting indicator for electrical cooking apparatus which is ofsimplified and rugged construction which lends itself to economy ofmanufacture.

Other and further objects and advantages of the present invention willbe apparent from the following description of a preferred embodimentthereof applied to an electric range. This preferred embodiment includesa stationary lamp positioned to direct a light beam toward the controlknob for the heating unit and a movable plate between the lamp and thecontrol knob which presents an aperture through which the light passesto the control knob. The spacing of this plate from the lamp isdetermined by the setting of the control knob and the size of the lightspot visible on the control knob is correspondingly varied so as to givea high noticeable visual indication of the heat setting.

In the drawings:

Figure 1 is a perspective view, with parts broken away for clarity,showing the present assembly viewed from the back of the control knob;and

Figure 2 is a longitudinal section through the Figure l assembly.

Referring to the drawings, a physical support forthe heat control andindicator in the present invention is in the form of a sheet metalbracket 10 which has its front wall 11 suitably fastened to thesplash-back panel 12 of an electric range. The rearwardly extendingbottom wall 13 of the bracket supports the housing 14 of a contop burneron the range. The'adjustable portion of the control is coupled to arotary stem 15, which projects through the housing 14 and up beyond thebottom wall 13 of the supporting bracket. A bevel gear 16 is suitablyaflixed to stem 15, such that turning of this gear causes the controlsetting to be changed accordingly.

As shown in Fig. 2, the splash-back panel 12 is formed with a forwardlyprojecting annular flange 12011 which defines a circular opening. Thebracket front wall 11 has a forwardly and rearwardly projecting annularflange 11a snugly received in this opening in the splash-back panel anddefining a circular opening 11b.

A manually rotatable control knob 17 is positioned at the front of thesplash-back panel 12. The control knob is mounted on a tubular outersleeve 18 by means of internal splines 19 on the control knob receivedsnugly in complementary external grooves on the forward end of sleeve18. With this arrangement, the sleeve 18 turns as a unit with controlknob 17. The sleeve 18 extends back through the splash-back panel 12 andthe opening 11b in the front wall 11 of the support bracket. At its rearend the sleeve 18 carries an integral bevel gear 20, which meshes withthe bevel gear 16 for the control. Thus, when the control knob 17 isturned to a particular angular position the setting of the control isadjusted accordingly.

Adjacent its front end, which is disposed within the axial opening incontrol knob 17, the outer sleeve 18 carries a metal retaining ring 21.One end of a compression coil spring 22 abuts against this ring. Theother end of this spring abuts against the front end of a hollow innersleeve 23. Sleeve 23 is keyed to sleeve 18 by means of an integrallongitudinal spline 24 on the top of sleeve 23, which is received in acomplementary longitudinal internal groove 25 in sleeve 18. The back endof sleeve 23 presents a cam surface 26 which is biased by spring 22 intoengagement with the cylindrical periphery of the hub 16a of bevel gear16.

A lamp bulb 27 is fixedly supported by means of a spring clip 28 mountedon the back end of the upper wall 29 of support bracket 10. This bulb ispositioned to direct a beam of light onto the transparent front panel 30of the control knob 17. A shutter arrangement in the form of an opaqueplate 31 with a central aperture 32 is provided to control the size ofthe light beam impinging on the control knob. Plate 31 is securedagainst an internal transverse annular shoulder 33 on the sleeve 23 bymeans of a retaining ring 34. Thus, the plate 31 moves toward or awayfrom the lamp bulb 27 to vary correspondingly the size of the light spoton the control knob as the inner sleeve 23 slides within the outersleeve 18.

In the overall operation of the above described arrangement, when thecontrol knob is in its extreme clockwise position (viewed from thefront), the high point 26a of the cam surface on sleeve 23 engages thehub 16a of the gear 16. This positions sleeve 23 at its extreme forwardposition (against the bias of spring 22) and the apertured plate 31 isremote from the lamp 27; This is the off position of the control knob,with the control at its zero setting. At this time the lamp 27 isextinguished by means of a suitable limit switch (not shown) operated bythe control knob.

If it is desired to go through progressively higher heating temperaturesettings, the control knob 17 is turned counter-clockwise (viewed fromthe front), the control stem 15 being turned correspondingly throughgears 20 and 16 to set the control to establish the cooking temperaturecalled for by the control knob. At the same time, the progressivelydeclining cam surface 26 on the sleeve 23 rides across the gear hub 16aunder the influence of the spring 22, and the apertured plate 31 carriedby this'sleeve moves toward the'lamp bulb 27. With the lamp-bulb nowilluminated, the'size of the light spot impinging on the front of thecontrol knob increases as the plate aperture 32 is positionedprogressively closer to the lamp bulb. Thus, the temperature setting towhich the control knob is turned determines the size of the light spotvisible on the front of knob.

Alternatively, starting from the off position the heat control can beturned rapidly to the full on setting simply by turning the control knob17 clockwise, so that the steep declining portion 26b of cam surface 26rides across the hub 16a.

Conversely, when it is desired to turn the heating unit off, the controlknob may be turned in either direction.

from the foregoing it will be apparent that the present inventionprovides an extremely effective, notice-catching arrangement forindicating visually the temperature setting of the heating unit.

While in the foregoing @scription the present invention has' beendescribed with reference to an electric range, it is to be understoodthat it may be used equally well in other types of cooking equipment,such as electric fry pans, electric roasters, gas ranges, and the like.

Also, while there has been described in detail and illustrated'in theaccompanying drawings a particular preferred embodiment of the presentinvention, it is to be understood that various modifications, omissionsand refinements which depart from the disclosed embodiment may beadopted without departing from the spirit and scope. of the presentinvention.

We claim:

l. In heating apparatus, the combination of adjustable means controllingthe heat setting of the apparatus, light source means for producing alight spot visible at the exterior of the apparatus, an apertured memberpositioned in front of said light source means to control the size ofsaid light spot, and means for adjustably positioning said aperturedmember toward or away from said light source means in response to thesetting of said adjustable means to thereby control the size of saidlight spot in accordance with the heat setting of the apparatus.

2. In electrical cooking apparatus, the combination of a rheostat forcontrolling a heating element in said cooking apparatus, a rotatablecontrol knob coupled to said rheostat to determine the setting of therheostat, a light source positioned behind said control knob to direct alight spot toward the control knob, a plate between the light source andthe control knob and having a circular aperture through which the lightshines from the light source onto the control knob, and means foradjusting the positionof said plate toward and away from the lightsource in response to the adjustment of the control knob to therebycontrol the size of the circular light spot on the control knob inaccordance with the rheostat setting.

3. In cooking apparatus, the combination of a manually rotatable controlknob for controlling the temperature setting of the apparatus, saidcontrol knob having a lighttransmitting portion, a light sourcepositioned to direct a beam of light toward said light-transmittingportion of the control knob, an apertured member positioned between thelight source and said light-transmitting portion of the control knob tocontrol the size of the light spot on said light-transmitting portion ofthe control knob, and means for positioning said apertured member towardor away from said light source in accordance with the angular positionof the control knob to thereby control the size of .said light spot inaccordance with the temperature setting of the apparatus.

4. In cooking apparatus, the combination of a first bevel gear coupledtothe heat control means for the apparatus and presenting a cylindricalhub, a manually rotatable control knobhaving a light-transmittingportion, an outer sleeve coupled to the control knob to turn therewithand carrying a second bevel gear which meshes with said first bevelgear, an inner sleeve coupled to said outer sleeve to turn therewith andslidable axially within said outer sleeve, said inner sleeve carrying acam surface remote from the control knob, spring means biasing the innersleeve to position said cam surface in engagement with the periphery ofsaid hub on the first bevel gear, a lamp bulb fixedly positioned withinsaid inner sleeve to direct a beam of light toward saidlight-transmitting portion of the control knob, and an opaque platecarried by the inner sleeve and positioned to intercept said beam oflight, said plate presenting an aperture which passes light from saidbulb to said light-transmitting portion of the control knob to produce avisible light spot on the control knob whose size is determined by thespacing of said opaque plate from the bulb.

5. In cooking apparatus having an adjustable heat control means having aportion with a peripheral surface thereon, the combination of a manuallyrotatable control knob having a light-transmitting portion and coupledto the heat control means to determine the latters setting, a sleevecoupled to the control knob to turn therewith and slidable axiallytoward and away from said light-transmitting portion of the controlknob, said sleeve carrying a follower surface remote from saidlight-transmitting portion of the control knob, spring means biasing thesleeve axially to position said follower surface in engagement with saidperipheral surface on the heat control means, one of said surfaces beinga cam surface so that rotation of the control knob causes the innersleeve to be displaced axially toward or away from said light-tranmitting portion of the control knob, a lamp fixedly positioned to directa beam of light toward said light-transmitting portion of the controlknob, and an opaque member carried by the inner sleeve to move axiallytherewith, said opaque member being positioned between said lamp andsaid light-transmitting portion of the control knob to intercept saidbeam of light, said opaque member having an aperture which passes lightfrom said lamp to said light-transmitting portion of the control knob toproduce a visible light spot on the control knob whose size isdetermined by the spacing of said opaque memberfrom the lamp.

6. The apparatus of claim 5, wherein said peripheral surface on theheat'control means is a cylindrical surface which extends around an axisperpendicular to the axis of said sleeve, and said follower surface onthe sleeve is a cam surface which-faces away from saidlight-transmitting portion of the control knob and has tangentialengagement with said cylindrical peripheral surface on the heatcontrol-means.

7. In cooking apparatus having an adjustable heat control means having aportion with a peripheral surface thereon,.,the combination-of amanually adjustable control member coupled to the heat control means-todetermine the latters setting, a light source positioned to produce abeam of light visible at the exterior of the apparatus, an aperturedmember positioned in front of said light source to control the size ofthe light spot visible at the exterior of the apparatus, and a followermember carrying said apertured member and slidable toward and away fromsaid light source, said follower member carrying a follower surfacewhich engages said peripheral surface on the heat control means, one ofsaid surfaces being a cam surface so that the adjustment of said controlmember to adjust the setting of the heat control means also adjusts theapertured memberslidably toward or away from said lightisource tocontrol the size of the lightspot visible at the exterior of theapparatus.

References Cited in the file of this patent UNITED STATES PATENTS2,424,575 Aves July 29, 1947 2,693,165 Appleman Nov. 2, 1954 2,701,541Miller Feb. 8 1955

